MACROMEDIA FLASH MEDIA SERVER 2-SERVER MANAGEMENT ACTIONSCRIPT LANGUAGE Manuale Utente Scaricare il pdf (Pagina 149)

ADOBE FLASH MEDIA INTERACTIVE SERVER

Server-Side ActionScript Language Reference

146

XMLSocket class

The XMLSocket class implements client sockets that let Flash Media Interactive Server communicate with a server

identified by an IP address or domain name. The XMLSocket class is useful for client-server applications that require

low latency, such as real-time chat systems. A traditional HTTP-based chat solution polls the server frequently and

downloads new messages by using an HTTP request. In contrast, an XMLSocket chat solution maintains an open

connection to the server, which lets the server send incoming messages immediately, without a request from the

client.

Note: You can also use the XMLSocket class to create an XMLStreams object. See XMLSocket constructor and

XMLStreams class.

To use the XMLSocket class, the server computer must run a daemon that understands the protocol used by this

class. The protocol has the following characteristics:

• XML messages are sent over a full-duplex TCP/IP stream socket connection.

• Each XML message is a complete XML document, terminated by a zero (0) byte.

• An unlimited number of XML messages can be sent and received over a single XMLSocket connection.

The following restriction applies to how and where an XMLSocket object can connect to the server:

• The XMLSocket.connect() method can connect only to TCP port numbers greater than or equal to 1024. One

consequence of this restriction is that the server daemons that communicate with the XMLSocket object must also

be assigned to port numbers greater than or equal to 1024. Port numbers less than 1024 are often used by system

services such as FTP, Telnet, and HTTP, which prohibits XMLSocket objects from these ports for security reasons.

The port number restriction limits the possibility that these resources can be inappropriately accessed and abused.

To use the methods of the XMLSocket class, you must first use the constructor,

new XMLSocket(), to create an

XMLSocket object.

Availability

Flash Media Server 2

Property summary

Method summary

Property Description

XMLSocket.maxUnprocessedChars The number of characters the connection can receive from the XML server without receiving

an end tag or the XMLSocket connection closes.

Method Description

XMLSocket.close() Closes the connection specified by the XMLSocket object.

XMLSocket.connect() Establishes a connection to the specified Internet host by using the specified TCP port (must

be 1024 or higher), and returns true or false, depending on whether a connection is

successfully established.

XMLSocket.send() Converts the XML object or data specified in the object parameter to a string and transmits

it to the server, followed by a zero (0) byte.

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MACROMEDIA FLASH MEDIA SERVER 2-SERVER MANAGEMENT ACTIONSCRIPT LANGUAGE Manuale Utente Pagina 149